The invention disclosed herein relates generally to a method and apparatus for moistening gummed envelope flaps and, more particularly, to a non-contact apparatus for application of moisture to gummed envelope flaps.
Envelope flap moistening systems generally fall into two categories: contact and non-contact moistening systems. Contact systems generally deposit moisture onto an envelope flap by contact with a wetted substrate. Non-contact systems generally spray moisture onto the envelope flap. In non-contact flap moistening systems, envelope flap moistening has been performed with nozzle and pump systems. The pump, which is connected to a reservoir, draws fluid from the reservoir and sprays the fluid through the spray nozzles.
In contact systems, the moisteners typically consist of contact media such as brushes, manifolds, foam or felt. Contact moisteners wick moistening fluid and distribute it onto a gummed envelope flap by making contact with the flap. The nature of contact systems make them subject to wear and sensitive to envelope flap deformations such as curl. Curled flaps can cause incomplete contact which leads to incomplete sealing. Contact systems tend to lose their wicking ability due to contamination of the media by the envelope gum and paper dust and also due to wear of the contact media from repeated abrasions. Additionally, contact systems need to provide contact between the glue line and the contact media for a particular time period in order for the glue to become sufficiently moistened for sealing.
Non-contact systems with pumps and nozzles can be open flap systems or closed flap systems. An open flap system is one in which the envelope flap is substantially open approximately 30xc2x0 to 60xc2x0 to the envelope. A closed flap system is one in which the envelope flap is opened slightly and a wick or nozzle array applies fluid at a close range onto the flap. In closed flap systems, there is a risk of contact between the nozzle and the envelope flap which causes contamination of the nozzles with envelope gum. Additionally, in pump and nozzle systems, fluid such as water is pumped through the nozzles. The pump requires a filter to protect the pump valves from paper fiber contamination, bacteria and other contaminates that can be present in the fluid. In fluid pumping systems, the pump always needs to be primed. In systems where fluid is being pumped intermittently, priming of the pump is critically important for reliably moistening each envelope flap. Fluid pumping system costs are high due to the need to reliably pump and filter the moistening fluid.
Thus, one of the problems of the prior art is that the contact systems and non-contact systems are subject to contamination. Another problem of the prior art is that nozzle and pump flap moistening systems are dependent upon the pump being primed. Another problem of the prior art is that nozzle and pump systems are expensive. Another problem of the prior art is that contact systems are sensitive to flap deformation. Another problem of the prior art is that contact systems are subject to wear. Another problem of the prior art is that contact systems require long contact periods in order to moisten the flap sufficiently.
This invention overcomes the disadvantages of the prior art by providing a non-contact apparatus for moistening envelope flaps that projects moistening fluid without pumping fluid. The present invention is directed to, in a general aspect, a non-contact envelope flap moistening apparatus which can be installed in a mailing machine apparatus. The apparatus for delivering moistening fluid to an envelope flap comprises: a) a reservoir containing the moistening fluid; b) a media partially submerged in the moistening fluid contained in the reservoir, the media wicking a portion of the moistening fluid as the media is moved through the reservoir and the moistening fluid; c) a drive means operably connected to the media for moving the media through the reservoir; d) a projecting means for projecting moistening fluid from the media, the projecting means positioned adjacent to the media on a side opposite the envelope flap and near a portion of the media that is not submerged in the reservoir; and e) whereby, when the projection means affects the media, a portion of the moistening fluid that has been wicked by the media is dislodged from the media forming droplets that travel to and moisten the envelope flap. The projecting means may be a nozzle connected to an air source for blowing air toward the media and the envelope flap, or it may be an actuator for causing vibration of the media and causing projection of moistening fluid from the media.
Thus, an advantage of the method of the present invention is that it accomplishes flap moistening without pumping fluid. Another advantage of the present invention is that the air source does not require expensive filtering since it is not subject to contamination. Another advantage of the present invention is that it is less costly. Another advantage of the present invention is that it is not subject to wear from contact with envelope flaps. Another advantage of the present invention is that it is not sensitive to mailpiece deformation. Another advantage of the present invention is that it does not require contact time for moistening. Other advantages of the invention will in part be obvious and will in part be apparent from the specification. The aforementioned advantages are illustrative of the advantages of the various embodiments of the present invention.